1. Field of the Invention
The present invention relates to a switch and particularly to a dustproof and waterproof switch.
2. Description of Related Art
It is known that the switch has been used for years in the field of power supply as a required device for controlling the power on or off and avoiding accidents caused by continuing supplying the power. The switch usually can be classified into a constant on switch, which is off at the time of the current being not taken, and a constant off switch, which is on at the time of the current being taken. Thus, products powered by the electricity have provided with a switch and the basic principle for operating a switch is in that two electric poles are utilized to connect with each other as a close circuit for constituting a state of current taking and the two electric poles disconnect from each other as an open circuit to form a state of current not taking.
Generally, safety is also an important factor has to be considered in addition to an accurate operation of power on or power off. For instance, the switch has to be free from leakage of electricity and incorrect connection. Besides, the switch has to be dustproof and waterproof in special locations such as a working environment with floating power dust or heavy moisture such that it can prevent the contact pole device in the switch from short circuit or corrosion and prolong the life span of the switch. A Taiwanese utility model No. 202467 (corresponding U.S. Pat. No. 6,713,697) discloses a dust and moisture switch, which includes a casing with the bottom thereof being inserted with a stationary pole plate and a support pole plate, an arc contact pole being lap joined to the support pole and being possible to swing leftward and rightward, a catch plate at the bottom thereof having a central hollow rod fitting with an extendable stir lever with the stir lever at the lower end thereof contacting with the arc contact pole, and an isolation part made of soft high molecular plastics for being passed through by and fitting with the stir lever so as to be located at and tightly joined to the inner walls of the casing. Thus, an effect of preventing the power dust and moisture from entering the bottom of the casing can be performed. However, the prior art is belonged to inner covering type isolation and the isolation part is made of high molecular plastics and is disposed between the catch plate and the casing so as to block the power dust and the moisture entering the bottom of casing so that the contact pole device can be free from foreign influence.
The crux of the present invention is to provide a dustproof and waterproof switch, which includes a hollow casing, having a bottom with two pole holes, extending outward a case frame from a top thereof and providing a support member at an inner wall thereof; a contact pole device, having a stationary pole and a support pole being inserted into and locating at one of the pole holes and having an arc pole attached to a top of the support pole such that the arc pole can swing leftward and rightward; an axial joint member, being disposed in the casing and lap joining with the support pole, providing a central fitting hole with a front side and a rear side of which extending a joining plate; a catch member, being provided with a shape of frame with a concave downward upper plane at the central top thereof, having a front and a rear walls with an axial hole respectively to correspond to the two axial projections, at a bottom thereof extending downward a hollow post for receiving and locating an extendable stir rod, an elastic piece being placed between the hollow post and the stir rod to allow the stir rod contacting with the arc contact pole constantly; and a covering member, being made of high molecular plastic material, having inner walls of an arc recess part at a top thereof joining with the concave downward upper plane of the catch member by way of injection molding and having a joining rim at a bottom edge thereof for fitting with the casing frame and closing an upper part of the casing completely. An end of the covering member is pressed down, the stir rod can slide on the arc contact pole to selectively contacts with or detaches from a stationary contact pole in the switch for performing power on or off.